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Data Transfer and Uncompression Information

Land Cover/Use and Aquatic Areas Data Sets

Transfer Options

   ArcInfo Export Data - UNIX format files: Most of the land cover/use and aquatic areas data sets were created using the GIS software program ArcInfo on a UNIX workstation. These data are served as double precision ArcInfo export files that have been compressed using the utility program Gzip. Most of the major GIS software packages are capiable of reading these export files.

To restore the data:

1. Download and store the compressed file(s) on your computer.
2. Uncompress the file(s) using "gunzip." If you do not have a copy of the gzip utilities, they're available via anonymous ftp from prep.ai.mit.edu:/pub/gnu.
3. Use your GIS program's Import routine against the export file (.e00) to create a coverage you can use.

   ArcInfo Export Data - PC/NT format files: Most of the land cover/use and aquatic areas data sets were created using the GIS software program ArcInfo on a UNIX workstation. These data are served as double precision ArcInfo export files which were then transferred to a PC format computer and the UNIX to DOS conversion was performed. The files were then compressed and self uncompressing executeables were created using WinZip. Most of the major PC based GIS software packages are capiable of reading these export files.

To restore the data:

1. Download and store the compressed file(s) on a personal computer (PC) or NT workstation.
2. Uncompress the data by activating the .exe file.
   Use a Windows 3.1 File Manager or a Windows 95, 98, or 2000's Windows Explorer, or NT Explorer program to locate the executeable (.exe file) on your hard drive. Activate the uncompression routine by double clicking on the file name. If you need to add any additional information like identifying an output directory, the uncompression program will prompt you for this information.
3. Use your GIS program's Import routine against the export file (.e00) to create a coverage you can use.

   ArcView Shape Files: The ArcView shape files containd double precision data that was compressed using the software program WinZip. These files are stored as PC/NT format data, if you want to transfer them to a UNIX computer the shape files are transferred as binary format data. Any legend (.avl) or metadata (.txt) files stored with the data should be transfered using ASCII protocols, so a DOS to UNIX file conversion will be performed.

Export files created after June 1, 2001 are available in two different mapping datums, North American Datum 1927 (nad 27) and North American Datum 1983 (nad 83). Shapefiles can may also be available in more than one projection, depending upon the area where the data are located.

To restore the data:

1. Download and store the compressed file(s) on a personal computer (PC) or NT workstation.
2. Uncompress the data by activating the .exe file.
   Use a Windows 3.1 File Manager or a Windows 95, 98, 2000's Windows Explorer, or NT Explorer program to locate the executeable (.exe file) on your hard drive. Activate the uncompression routine by double clicking on the file name. If you need to add any additional information like identifying an output directory, the uncompression program will prompt you for this information.
3. The uncompressed files are ready to use. If you're accessing these data using ArcView GIS software, use the Add Theme function to locate and add the shape file to a view window.

   Metadata: Metadata for the land cover/use and aquatic areas data sets are stored as ASCII text files. The files are viewable by clicking on the metadata graphic. To download the metadata file, either hold the computer's mouse over the metadata graphic and press the mouse's right-hand mouse button or use which ever option your web browser contains for saving files.